• Journal of Advanced Marine Engineering and Technology
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• v.31 no.3
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• pp.243-251
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• 2007

This experiment was conducted to investigate the effect of particles on the heat transfer characteristics of fluids flowing in a cold water tube. Plastic beads with 3 different sizes were used as flowing particles with cold water. An experimental test section was composed of concentric double tubes having diameters of 25mm for the inner tube and 50mm for the outer tube. The materials for the inner and outer tubes are copper and PVC respectively. It was found that the particles enhanced the heat transfer coefficient by random and vortex motion in the fluid. Hence the heat transfer coefficients for the fluid with 2mm, 5mm and $2{\times}6mm$ particles were $7%{\sim}37%$ higher than the fluid without the particles.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2328-2333
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• 2008

The experimental study was carried out to evaluate the heat transfer performance on the shell side of shell-and-plate finned tube heat exchanger with three different tube numbers(9, 13 and 19). Oil flowing on the shell side was cooled by cold water flowing inside the tubes. A shell-and-tube heat exchanger of an oil cooler consisted of one shell pass and two tube passes with the inner tube diameter of 8.82 mm and the tube length of 575 mm. Mass flow rate was varied from 1.2 to $6.0\;m^3/h$ for oil and from 0.6 to $3.0\;m^3/h$ for cold water, respectively. From the experiment of shell-and-plate finned tube heat exchanger, the shell side heat transfer coefficient of heat exchanger with 9 tubes was compared with that of 13 and 19 tubes. It was found that the heat exchanger with 9 plate finned tubes showed more performance of heat transfer than that of 13 and 19 tubes.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.5
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• pp.680-686
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• 1998

In the adoption of a desalination system the most important factor is the cost of fresh water pro-duction. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$ When it is serviced however the LNG absorbs energy from a heat source and it is transformed to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energycan be utilized to produce fresh water by using a sea water freez-ing desalination system. in order to develop a sea water freezing desalination system and to estab-lish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water in a cooled circular tube to measure the freezing rate and to investigate the freezing heat-transfer characteristics. The experimental results provide a general understanding of sea water freezing behavior in a cooled circular tube.

• International Journal of Advanced Culture Technology
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• v.3 no.2
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• pp.124-131
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• 2015

Computational fluid dynamics (CFD) has been employed for the Heat exchanger efficiency of a counter flow heat exchanger. The Heat exchanger efficiency has been assessed by considering the computed Nusselt number and flow friction characteristics in the double pipes heat exchanger equipped with two types twisted-tapes: (1) single clockwise direction and (2) alternate clockwise and counterclockwise direction. Cold and hot water are used as working fluids in shell and tube side, respectively. Hot and cold water inlet mass flow rates ranging are between 0.04 and 0.25 kg/s, and 0.166 kg/s, respectively. The inlet hot and cold water temperatures are 54 and $30^{\circ}C$, respectively. The results obtained from the tube with twisted-tapes insert are compared with plain tube. Nusselt number and friction factor obtained by CFD simulations were compared with correlations available in the literature. The numerical results were found in good agreement with the results reported in literature.

• Nuclear Engineering and Technology
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• v.38 no.5
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• pp.455-458
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• 2006

The HANARO reactor has a vertical hole for a cold neutron source (CNS) in the heavy-water reflector tank, i.e., the CNS hole, which was considerably deformed during its welding to the horizontal cold neutron (CN) beam tube. This paper presents an investigation of the form of the CNS hole for the optimal design of the a vacuum chamber for the CNS. In addition, the installation method of the vacuum chamber into the CNS hole for minimizing the water thickness between the vacuum chamber and the nose of the CN beam tube is proposed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.1
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• pp.108-116
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• 2001

The vortex tube is a simple device which separates fluid stream into a cold stream and a hot stream without any chemical reaction. The process of energy separation in the vortex tube has caused a great deal of interest. Although many studies on energy separation in the vortex tube using air as the working fluid have been made so far, few experimental studies treated energy separation for incompressible fluid. So, an experimental study for the energy separation in the vortex tube using the water which is essentially an incompressible fluid is presented. When working fluid is the water, the best geometric values of nozzle area ratio and number of nozzle holes are 0.155, 6 respectively. These geometric values are showed by the similar values which are presented by compressible fluid as working fluid. But hot side mass fraction of which maximum temperature drop is happened are different from compressible fluid.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.981-988
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• 2018

An experiment was performed for the OECD/NEA ROSA-2 Project with the large-scale test facility (LSTF), which simulated a steam generator tube rupture (SGTR) accident due to a double-ended guillotine break of one of steam generator (SG) U-tubes with operator recovery actions in a pressurized water reactor. The relief valve of broken SG opened three times after the start of intact SG secondary-side depressurization as the recovery action. Multi-dimensional phenomena specific to the SGTR accident appeared such as significant thermal stratification in a cold leg in broken loop especially during the operation of high-pressure injection (HPI) system. The RELAP5/MOD3.3 code overpredicted the broken SG secondary-side pressure after the start of the intact SG secondary-side depressurization, and failed to calculate the cold leg fluid temperature in broken loop. The combination of the number of the ruptured SG tubes and the HPI system operation difference was found to significantly affect the primary and SG secondary-side pressures through sensitivity analyses with the RELAP5 code.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.3
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• pp.201-207
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• 2000

In this study, methodologies for checking the interference between in-core instrumentation (ICI) guide tubes for routing of ICI guide tubes in the reactor coolant system of typical Pressurized Water Reactor under cold and normal operation (NOP) conditions are presented. The closest points of ICI guide tubes under cold condition are calculated by using minimize technique and are used as data for NOP analysis. Movements of ICI guide tubes under NOP condition are performed by the commercial computer code, SUPERPIPE.

• Animal Systematics, Evolution and Diversity
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• v.32 no.3
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• pp.197-206
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• 2016

Two cold-water coral taxa, Octocorallia in the class Anthozoa and Stylasteridae in the class Hydrozoa, were identified. Deep-water samples were collected in fishing nets at depths ranging between 20 and 200 m along the coasts of the East Sea in Korea from 1976 to 1993. The two species found in this study represent new records for Korea: Paragorgia arborea (Linnaeus, 1758) in the class Anthozoa, and Stylaster profundiporus Broch, 1936 in the class Hydrozoa. Two families, Paragorgiidae and Stylasteridae, are also newly recorded in Korea. Furthermore, the species name of another cold-water gorgonian species, Primnoa pacifica (Kinoshita, 1907) in the family Primnoidae, is amended in this report. The two newly recorded cold-water coral species from Korea are described in detail based on their morphological characteristics. Paragorgia arborea is characterized by its growth form, medulla and cortex, zooid dimorphism, canal system, and spicule composition. Stylaster profundiporus is distinguished by its external skeletal characteristics, such as the coordination of dactylopores and gastropores, presence or absence of gastrostyles and dactylostyles, cyclosystem orientation, ampullar position, gastropore tube shape, and coenosteal texture.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.9
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• pp.845-852
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• 2001

The phenomena of energy separation in vortex tubes was investigated experimentally to see the effects of the conductivity of a tube and convective heat transfer on the outer surface of a tube. The experiment was carried out with different conductivity (pyrex, stainless steel and copper) of a tube and three kinds of convective heat transfer modes (adiabatic condition, natural convection (air) and forced convection (water) on the outer surface of a tube. the results were obtained that hot exit fluid temperature was highly affected by a change of conductivity of a tube when the outer surface was cooled by the forced convection of water. However, the cold exit temperature was little affected by heat transfer modes on the outer surface in vortex tubes.